It is reported that stampede accidents in the worldwide are common in that in a crowded and noisy environment, policemen for rescue are trapped in the crowds and fail to reach the accident spots to give guidance and evacuation. During the night, evidence taking and alarming are especially hard. If a small-sized device integrating a speaking and illumination, imaging and evidence taking is provided for the policemen to carry by themselves or carried on unmanned aerial vehicle, occurrences of such stampede accidents may be effectively prevented, or effective assistance may be given in case of occurrence of such accidents. With small modularization of LED packaging and miniaturization of cameras, it is possible to design such small-sized devices integrating the functions of speaking and illumination, imaging and evidence taking.